The answers to your questions are all rooted in basic business management. It's data driven decisions. Not always the best course of action, but it's what they've done here.
Renovations: Renovation can make upkeep and repairs more efficient by standardizing the materials, layout and architecture. Simplifying the interiors leads to faster cleaning times and easier maintenance (again, less costly). It can also increase equity in the properties by making the buildings readily sellable without having to spend money to strip the property of excess branding or decorations.
Menu Changes: Getting rid of items that don't sell often, or require 1 off ingredients that can't be used in other dishes leads to easier and more efficient supply chain management. Less room in freezers and fridges taken up by items that don't turn as high a profit as others. It also reduces the complexity of the dishes, making staffing easier and cheaper because you can pay retards to make it.